71766661 has 4 divisors (see below), whose sum is σ = 72477324. Its totient is φ = 71056000.

The previous prime is 71766641. The next prime is 71766703. The reversal of 71766661 is 16666717.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45562500 + 26204161 = 6750^2 + 5119^2 .

It is a cyclic number.

It is not a de Polignac number, because 71766661 - 2¹¹ = 71764613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71766631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 355180 + ... + 355381.

It is an arithmetic number, because the mean of its divisors is an integer number (18119331).

Almost surely, 2^71766661 is an apocalyptic number.

It is an amenable number.

71766661 is a deficient number, since it is larger than the sum of its proper divisors (710663).

71766661 is a wasteful number, since it uses less digits than its factorization.

71766661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 710662.

The product of its digits is 63504, while the sum is 40.

The square root of 71766661 is about 8471.5205836969. The cubic root of 71766661 is about 415.5668665070.

It can be divided in two parts, 71766 and 661, that added together give a palindrome (72427).

The spelling of 71766661 in words is "seventy-one million, seven hundred sixty-six thousand, six hundred sixty-one".